井间地震速度和Q值联合层析成像及应用

Joint tomographic imaging for cross-hole seismic velocity and Q value.

井间地震速度层析成像可用来解决油田井间储、盖层横向的连通性、纵向的接触关系等问题 ;井间地震的 Q值层析成像能反映井间介质对弹性波的吸收情况 ,可用于估算有关储层参数。通过利用井间地震初至波的旅行时及其频率特性进行地层地震速度和岩石 Q值的联合层析成像 ,就可以综合利用地震波的运动学和动力学特征对井间储层进行更精确的描述。 对于求解井间地震介质分布的定解问题 ,基于地震射线成像算法中的正问题对地震波慢度沿射线的积分表现为时间场 ,衰减因子沿射线的积分反映介质的吸收情况 ,两者均可用结构类似的Radon变换表征。因此 ,在反问题处理中手段基本相同 ,便于联合层析成像的实现。而井间采集的地震波初至数据反映了透射波频率随地层岩性及储层变化的情况 ,由此 。

Tomographic imaging for cross hole seismic velocity can be used to solve the problems such as lateral connectivity of reservoir and caprock in cross hole and vertical contacting relation in oilfield; tomographic imaging for cross hole Q value can reflect the absorption of elastic wave by cross hole medium and can be used to evaluate respective reservoir parameters. It can describe precisely the cross hole reservoir by using synthetically the kinematic and dynamic features through using travel time and frequency feature of cross hole seismic first break for joint tomographic imaging for seismic velocity of stratum and for Q value. For the purpose of fixed solution problem for finding solution of cross hole seismic medium distribution, forward problem based on seismic ray imaging algorithm consists of two parts: integration of seismic wave slowness along ray represents a time field; integration of attenuation factor along ray reflects absorption of medium. Both of them can be characterized by structural similar Radon transform. Therefore, processing measure is basically same in inverse problem and facilitate to fulfill the joint tomographic imaging. Seismic first break acquired from cross hole reflects variation of transmission wave frequency with strat um and reservoir, so it can strengthen knowledge of reservoir parameters by studying a relation of seismic wave frequency to attenuation factor.